This application claims a priority from German application 199 41 538.2, filed Sep. 1, 1999, and the contents of that priority application are incorporated herein by reference.
This invention relates to a device for receiving a gas discharge lamp of a type including a housing in which is arranged an igniting apparatus and which has an insertion opening in an outer wall thereof with recesses at an edge of the insertion opening for receiving radially projecting bayonet lugs of a lamp base inserted into the insertion opening for securing the lamp base axially when the lamp base is rotated into a locked rotational position, said device including a box on the housing for a feeder plug which provides an electric power supply.
Gas discharge lamps for vehicle headlights with a bayonet lock between the lamp base and a lamp receptacle are known. When no gas discharge lamp is inserted in the lamp receptacle, contacts for the power supply of the lamp are exposed. Thus, they are accessible when the gas discharge lamp is replaced, for example.
Gas discharge lamps must be supplied with a high voltage for the ignition process, thus care must be taken to ensure that the contacts which are exposed when a lamp is not inserted into the receptacle do not carry a voltage in order to ensure protection of anyone coming in contact with them. With automotive headlights that do not belong to this generic type, it is provided that a lamp receiver is arranged to have a first plug part which can be connected to a second plug part for an electric connection. Access to the lamp receptacle and thus to the gas discharge lamp requires that first the connection of the two plug parts be released, so that the lamp base does not carry a voltage (see German Patent Application 44 45 223 A1).
It is an object of this invention to provide a device for receiving a gas discharge lamp of the type mentioned in the opening paragraph above, having an integrated ignition device, which has mechanical blocking of a feeder-plug-insertion box arranged on the housing as long as a bayonet connection of a base of a gas discharge lamp is not in a locked rotational position therein.
According to principles of this invention, a latch is arranged in the housing such that the latch can be linked to at least one of bayonet lugs of a lamp base inserted into an insertion opening of the housing so that when the lamp base is rotated to the unlocked position, said latch is carried with it into a blocking position projecting into a plug area of a box on the housing.
It is essential for this invention that the latch which is movably arranged in the device housing is at the plug-in area of the box for the feeder plug if the base of the gas discharge lamp is not inserted into the lamp receptacle and screwed into the locked rotational position. As long as the latch is blocking the plug-in area of the box, the feeder plug cannot be inserted into it. Thus, the electric connection of the ignition device is interrupted, and the exposed contacts in the lamp base for the electric power supply to the gas discharge lamp are, accordingly, voltage free. For one thing, a coordination between the rotational position of the lamp base and the latch can make it so that it is impossible to turn the gas discharge lamp to the unlocked position when the feeder plug is inserted in the box. For another thing, it is possible for the feeder plug to be thrown out of the box on the device housing by the latch when the gas discharge lamp is turned to the unlocked position. A preferred embodiment of this invention involves providing a stop that can be overcome in the plug area of the box, with the latch engaging behind this stop in its rotational locked position, so that the latch cannot be pressed back into its unlocked position by pushing the feeder plug in the box. The latch can be secured in its final locked position especially well by a form-fitting interengagement which can be overcome by a specific manipulation.
Additional advantageous enhancements of this invention are possible in further embodiments.